High school student Candy Christian wakes up from a daydream where she seemingly descends to Earth from space, in her father's social sciences class, causing much embarrassment. Following a poetry recital at Candy's school, eccentric Welsh poet MacPhisto offers her a ride home in his limousine. En route, MacPhisto forces himself on her but is unable to proceed after becoming too inebriated. With the help of her Mexican gardener, Emmanuel, Candy takes MacPhisto inside in order to help him out of his liquor-soaked clothes. In the basement, MacPhisto drunkenly recites poetry while humping a mannequin, inciting Emmanuel to sexually assault Candy. Scandalized upon walking in on the scene, Candy's uptight father decides to send her away to live with his twin brother Jack and his wife Livia in New York City.

At the airport, the family is accosted by Emmanuel's three vengeful sisters, who accuse Candy of corrupting their brother. During the scuffle, Candy's father is rendered unconscious due to a head injury. The Christians escape by boarding a military plane commanded by General Smight. In exchange for a blood transfusion for her father, General Smight orders Candy to undress, intending to impregnate her. Meanwhile, he accidentally pushes the button that signals his paratroopers to leap from the plane. Realizing this, General Smight jumps as well, only to slip out of his parachute harness.

Upon landing in New York, Dr. Krankheit meticulously performs surgery on Candy's father in front of an audience. When Uncle Jack attempts to seduce Candy during a post-operative cocktail party, the hospital's executive director, Dr. Dunlap, berates her for her perceived lewd behavior, causing her to faint. Dr. Krankheit takes Candy to another room and tricks her into sex by pretending to examine her. While searching for her father, Candy wanders back into the operating room to find that Dr. Krankeit has branded all the nurses with his initials, as he prepares to do so to Livia. When he attempts to have Candy captured so that she is next, she flees the hospital.

Roaming the streets of Manhattan, Candy ends up in a Sicilian bar in Greenwich Village, where she is beset by a group of mobsters. An offbeat underground filmmaker, Jonathan J. John, then takes her into the men's room and shoots her for a film. As the room floods due to broken pipes, two policemen arrive and assault Jonathan, whereupon a drenched Candy escapes. In Central Park, she meets a hunchback who takes her into a deserted mansion later that night. A gang of thieves walk in and proceed to ransack the place, while the hunchback rapes Candy on top of a grand piano. After arresting Candy, the two policemen maliciously plan to frisk her. However, they lose control of their squad car and crash into a club full of drag queens. As mayhem ensues, Candy escapes again.

The next morning, Candy asks for a ride in the back of a semi-trailer truck, which turns out to be the sanctum of Grindl, a sham guru. He teaches her the "seven stages of enlightenment" as a pretext to have sex with her. After several days on the road, Grindl informs Candy that a different guru will guide her through the rest of her journey. Upon arrival in California, Candy is chased through the desert by the New York police officers, but she manages to outwit them. Shortly thereafter, Candy finds her new guru—a robed figure with a toucan on his shoulder, his face covered with white clay. She follows him into an underground Hindu temple, which then partially collapses due to a cataclysm. As the two proceed to have sex, the guru's face is washed clean and Candy is shocked to discover he is actually her brain-damaged father.

As Candy wanders across a field—surrounded by flapping banners and hippies playing music—she revisits many of the characters she met throughout the film, before finally returning to outer space.